Attorneys for George Zimmerman yesterday deposed a woman who told Sanford police the night Trayvon Martin was shot she saw two figures fighting, "a heavier man on top."

Zimmerman outweighed the Miami Gardens 17-year-old by 45 pounds, according to prosecution records.

Defense attorneys have begun the long work of taking sworn statements from witnesses in the case. Paperwork released today by defense attorney Mark O'Mara's office show that yesterday, they took the deposition of a woman who called 911 the night of the shooting.

She is identified only by number, "witness 18." It's not clear what she told attorneys yesterday but when interviewed by Sanford police Feb. 26, the night of the shooting, she said she heard loud voices outside her window then heard them quiet, but they got loud again.

She could not see clearly, she said, but made out "two men on the ground … a heavier man on top."

"Then I heard someone desperately saying, 'Help, help.' " she said and called 911.

She heard "a pop," she said, "I heard it more than once."

According to prosecution records, Zimmerman fired once.

After that, the woman said she saw a "larger man" standing over the other, who was still on the ground.

Zimmerman is the 29-year-old Neighborhood Watch volunteer who says he shot Trayvon in self-defense after the teenager floored him with one punch then climbed on top and began hammering his head on a sidewalk.

Zimmerman is charged with second-degree murder.

Several witnesses saw or heard parts of the confrontation between the two that night, but no one saw it begin, according to Sanford police.

One of the key points of dispute is who was on top during what several witnesses have described as a fight or wrestling match between the two.